Process for liquefying a cellulosic material and its products

ABSTRACT

A process for liquefying a cellulosic material to produce a liquefied product from cellulosic material is provided. Products obtained from such process and use of such products to prepare biofuels is also provided.

This application claims the benefit of European Application No.10162722.2 filed Mar. 12, 2010, which is incorporated herein byreference.

TECHNICAL FIELD OF THE INVENTION

The present invention relates to a process for liquefying a cellulosicmaterial. The process provides a liquefied product which may beconverted into biofuel components for use in fuel formulations.

BACKGROUND OF THE INVENTION

Cellulosic materials which may be converted into valuable intermediates,which intermediates may be further processed into fuel components, areof considerable interest as feedstocks for the production of sustainablebiofuels. Biofuels are combustible fuels, that can be derived frombiological sources. The use of such biofuels results in a reduction ofgreenhouse gas emissions. Such biofuels can be used for blending withconventional petroleum derived fuels. Biofuels used for blending withconventional gasoline fuels include alcohols, in particular ethanol.Biofuels such as fatty acid methyl esters derived from rapeseed and palmoil can be blended with conventional diesel fuels. However, thesebiofuels are derived from edible feedstock and so compete with foodproduction.

Biofuels derived from non-edible renewable feedstocks, such ascellulosic material, are becoming increasingly important, botheconomically and environmentally. In addition there has been muchinterest in developing improved methods for producing biofuels derivedfrom non-edible renewable feedstocks, such as cellulosic material. Fuelcomponents can be derived from cellulose derivatives using multistepprocesses, for instance levulinate (Bozels et al., Resources,Conservation and Recycling 2000, 28, 227), valerate (WO 2006/067171) orpentenoate (WO 2005/058793) esters from levulinic acid or methyl-furan(Roman-Leshkov et al., Nature 2007, 447, 982) or ethyl furfuryl ether(WO 2009/077606) from furfural.

It would, however, be advantageous to be able to convert cellulosicmaterial such as for example lignocelluloses into a liquefied product,which liquefied product could then be fed to an oil refinery forupgrading to fuel components.

WO 2005/058856 describes a process for liquefaction of cellulosicmaterial. In the process solid cellulosic material is heated in thepresence of an acid catalyst and a solvent. The solvent contains acompound having a gamma lactone group of a specific general molecularformula. Examples of such compounds that are mentioned includegamma-valerolactone. It is further indicated that also levulinic acid,furfural or compounds without a gamma lactone group that are obtainablefrom levulinic acid or furfural may be used as solvent in the process.The process is suitable for its purpose, but unfortunately the largeamounts of expensive solvent that are needed make the processeconomically less attractive.

U.S. Pat. No. 5,608,105 describes a process for producing levulinic acidfrom carbohydrate-containing materials. It describes as an examplereacting a slurry of paper sludge containing 3.5% by weight of theaqueous portion sulfuric acid with steam in a series of two reactors.The liquid product outflow contains levulinic acid at a concentration of0.68%. A disadvantage of the described process is that the processproduces large amounts of low-value insoluble humins and, therefore,offers poor utilization of the feedstock. In addition the process is anextensive process using two reactors.

There remains a continuing need for the development of improvedprocesses for liquefying cellulosic material.

SUMMARY OF THE INVENTION

Accordingly, in one embodiment of the present invention provides aprocess for liquefying a cellulosic material to produce a liquefiedproduct, which process comprises contacting the cellulosic materialsimultaneously with

(a) an acid catalyst;(b) a solvent mixture containing water and a co-solvent, whichco-solvent comprises one or more polar solvents and which co-solvent ispresent in an amount of more than or equal to 10% by weight and lessthan or equal to 95% by weight, based on the total weight of water andco-solvent;(c) a hydrogenation catalyst; and(d) a source of hydrogen.

The process allows for the simultaneous hydrolysis and hydrogenation ofthe cellulosic material.

In another embodiment of the present invention provides a productcomprising:

-   (a) in the range from 20 to 80 wt % of a monomeric fraction    containing one or more monomeric compounds having a molecular weight    (Mw) of less than or equal to 250 Dalton (Da);-   (b) in the range from 20 to 80 wt % of an oligomeric fraction    containing one or more oligomeric compounds having a molecular    weight (Mw) of more than 250 Dalton (Da),    wherein the percentage of saturated carbon atoms in the oligomeric    fraction is more than or equal to 35%, based on the total amount of    carbon atoms present.

In yet another embodiment of the invention provides a process forproducing a biofuel component from a cellulosic material, which processcomprises

(a) contacting the cellulosic material simultaneously with an acidcatalyst, a solvent mixture containing water and a co-solvent comprisingone or more polar solvents, a hydrogenation catalyst and a source ofhydrogen to produce a liquefied product;(b) obtaining one or more monomeric compounds and/or one or moreoligomeric compounds from the liquefied product obtained in step a) toproduce a second product comprising one or more monomeric compoundsand/or one or more oligomeric compounds;(c) hydrodeoxygenating and/or cracking at least part of the secondproduct obtained in step b) to produce a fuel component and/or fuelcomponent precursor;(d) blending and/or processing the fuel component and/or the fuelcomponent precursor in the preparation of a biofuel.

The process of the invention furthermore provides a novel productcontaining a substantial amount of tetrahydropyranic monomers and/oroligomers, which can be useful as a gasoline and/or diesel component.

In yet another embodiment of the invention provides a fuel compositioncomprising one or more tetrahydropyranic monomers and/or oligomers.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a schematic diagram of a first process according to theinvention.

FIG. 2 shows a schematic diagram of a second process according to theinvention.

FIG. 3 illustrates molecular structures of some of the monomericcompounds in example 19.

DETAILED DESCRIPTION OF THE INVENTION

It would for example be an advancement in the art to provide a processfor liquefying a cellulosic material having an increased degree ofliquefaction and a reduction in the amount of unwanted insoluble humins.It can furthermore be an advancement in the art to reduce the number ofprocess steps from cellulosic starting material to biofuel end product.

It has been found that the process according to the invention results inan increased degree of liquefaction of the cellulosic material, even athigh cellulose loading. It thereby delivers more valuable products, suchas monomeric and oligomeric compounds. With the process according to theinvention, such valuable monomeric and oligomeric compounds mayadvantageously be prepared from materials which are readily available.These monomeric and oligomeric compounds may subsequently be convertedinto other hydrocarbons or biofuels.

Further, the high degree of saturation of the produced monomeric and/oroligomeric compounds, results in improved chemical stability andincreased heating value of the product. This high degree of saturationmakes it possible to use the product of the process according to theinvention directly as a fuel component or to process the product in arefinery without any additional pretreatment.

In addition to the above, the process according to the invention offersprocessing efficiencies by allowing a reduction of the number of processsteps from a cellulosic starting material to a biofuel end product.

By liquefying is herein understood the conversion of a solid material,such as cellulosic material, into one or more liquefied products.Liquefying is sometimes also referred to as liquefaction.

By a liquefied product is herein understood a product that is liquid atambient temperature (20° C.) and pressure (1 bar absolute) and/or aproduct that can be converted into a liquid by melting (for example byapplying heat) or dissolving in a solvent. Preferably the liquefiedproduct is liquid at ambient temperature (20° C.) and pressure (1 barabsolute).

Liquefaction of a cellulosic material can comprise cleavage of covalentlinkages in that cellulosic material. For example liquefaction oflignocellulosic material can comprise cleavage of covalent linkages inthe cellulose, hemicellulose and lignin present and/or cleavage ofcovalent linkages between lignin, hemicelluloses and/or cellulose.

As used herein, cellulosic material refers to material containingcellulose. Preferably the cellulosic material is a lignocellulosicmaterial. A lignocellulosic material comprises lignin, cellulose andoptionally hemicellulose. The process according to the invention makesit possible to liquefy not only the cellulose but also the lignin andhemicelluloses.

Any suitable cellulose-containing material may be used in the processaccording to the present invention. The cellulosic material for useaccording to the invention may be obtained from a variety of plants andplant materials including agricultural wastes, forestry wastes, sugarprocessing residues and/or mixtures thereof. Examples of suitablecellulose-containing materials include agricultural wastes such as cornstover, soybean stover, corn cobs, rice straw, rice hulls, oat hulls,corn fibre, cereal straws such as wheat, barley, rye and oat straw;grasses; forestry products such as wood and wood-related materials suchas sawdust; waste paper; sugar processing residues such as bagasse andbeet pulp; or mixtures thereof.

Before being used in the process of the invention, the cellulosicmaterial is preferably processed into small particles in order tofacilitate liquefaction. Preferably, the cellulosic material isprocessed into particles with an average particle size of 0.5 to 30 mm.If the cellulosic material is a lignocellulosic material it may alsohave been subjected to a pre-treatment to remove and/or degrade ligninand/or hemicelluloses. Examples of such pre-treatments includefractionation, pulping and torrefaction processes.

The, optionally pre-processed, cellulosic material can be simultaneouslycontacted with an acid catalyst, a solvent mixture containing water anda co-solvent comprising one or more polar solvents, a hydrogenationcatalyst, and a source of hydrogen. As indicated above, the processaccording to the invention can advantageously comprise the simultaneoushydrolysis and hydrogenation of the cellulosic material, resulting in animproved degree of liquefaction. By simultaneous contact is understoodcontact of the cellulosic material with one of the specified claimfeatures in the presence of the remaining claim features. In this waysimultaneous hydrolysis and hydrogenation of the cellulosic material canbe effected as any hydrolysis product can be in-situ hydrogenated.

The acid catalyst for use in the process according to the invention maybe any acid catalyst known in the art to be suitable for liquefying ofcellulosic material. For example, the acid catalyst may be a Brönstedacid or a Lewis acid. Further the acid catalyst may be a homogeneouscatalyst or a heterogeneous catalyst. Preferably the acid catalyst is ahomogeneous or finely dispersed heterogeneous catalyst, most preferablythe acid catalyst is a homogeneous catalyst. Preferably the acidcatalyst remains liquid and stable under the process conditions of theinvention and preferably it is sufficiently strong to effect cleavage ofthe covalent linkages and dehydration of the cellulosic material.

Preferably the acid catalyst is a Brönsted acid and more preferably theacid catalyst is a mineral or organic acid, preferably a mineral ororganic acid having a pKa value below 3.75, more preferably a mineral ororganic acid having a pKa value below 3, and most preferably a mineralor organic acid having a pKa value below 2.5.

Examples of suitable mineral acids include sulphuric acid, para toluenesulphonic acid, nitric acid, hydrochloric acid and phosphoric acid, andmixtures thereof. In a preferred embodiment, the acid catalyst used inthe process of the invention is sulphuric acid or phosphoric acid.

Examples of suitable organic acids which may be used in the process ofthe invention include oxalic acid, formic acid, lactic acid, citricacid, trichloracetic acid and mixtures thereof.

The acid catalyst is preferably present in an amount of less than orequal to 35% by weight, more preferably less than or equal to 20% byweight, even more preferably less than or equal to 10% by weight andmost preferably less than or equal to 5% by weight, based on the totalweight of solvent mixture and acid catalyst. Further the acid catalystis preferably present in an amount of more than or equal to 0.01% byweight, more preferably more than or equal to 0.1% by weight and mostpreferably more than or equal to 0.2% by weight, based on the totalweight of solvent mixture and acid catalyst. It will be appreciated thatfor any given acid catalyst the amount of acid required will depend onthe strength of the acid. In one preferred embodiment, the acid catalystis present in an amount of from 1% to 10% by weight, preferably from 2%to 5% by weight, based on the weight of solvent mixture and acid.

The solvent mixture contains water and a co-solvent, which co-solventcomprises one or more polar solvents. By a co-solvent, comprising one ormore polar solvents, is understood a solvent other than water.Preferably the co-solvent comprises more than two, more preferably morethan three polar solvents. In an especially preferred embodiment theco-solvent comprises at least a part of the liquefied product, whichpart of the liquefied product comprises one or more polar solvents.Advantageously, part of the liquefied product is therefore recycled tothe liquefaction process to be used as co-solvent. More preferably theco-solvent comprises at least two monomeric compounds obtained from theliquefied product as a polar solvent. Most preferably more than 50 w %of the polar monomeric compounds obtained from the liquefied product areused as polar solvent. There is no upper limit for the number ofdifferent polar solvents that may be contained in the co-solvent, but inpractice the number of different polar solvents in the co-solvent issuitably less than or equal to 500.

A measure of the polarity of a solvent is its log P value, where P isdefined as the partition coefficient of a compound in a two phaseoctanol-water system. The log P value can be determined experimentallyor calculated according to standard procedures as discussed in Handbookof Chemistry and Physics, 83^(rd) Edition, pages 16-43 to 16-47, CRCPress (2002).

In one embodiment the co-solvent is a solvent having a polarity of log Pless than +1. In another embodiment, the co-solvent is a solvent havinga polarity of log P less than +0.5. In a further embodiment, theco-solvent is a solvent having a polarity of log P less than 0.

The co-solvent can comprise any polar solvent that is stable under theliquefaction reaction conditions used and for the duration of thereaction time. Advantageously, the co-solvent may be water-miscible atthe reaction temperature employed.

Preferably one or more of the polar solvents in the co-solvent isderived from cellulosic, and preferably lignocellulosic, material. Morepreferably one or more of the polar solvents is a solvent obtainable byacid hydrolysis of cellulosic, and preferably lignocellulosic, materialsuch as for example acetic acid, formic acid and levulinic acid. Polarsolvents which are obtainable from such acid hydrolysis products byhydrogenation may also suitably be used. Examples of such hydrogenationproduct solvents include gamma-valerolactone which is obtainable fromlevulinic acid by hydrogenation, tetrahydrofufuryl and tetrahydropyranylcomponents which are derived from furfural or hydroxymethylfurfural,mono- and di-alcohols and ketones which are derived from sugars, andguaiacol and syringol components which are derived from lignin.Preferably the co-solvent for use according to the invention maycomprise one, two or more of such solvents.

The one or more polar solvents may comprise one or more carboxylicacids. By a carboxylic acid is herein understood an organic compoundcomprising at least one carboxyl (—CO—OH) group. In a preferredembodiment the co-solvent comprises at least one or more carboxylicacids. More preferably the co-solvent comprises equal to or more than 5wt % carboxylic acids, more preferably equal to or more than 10 wt %carboxylic acids, most preferably equal to or more than 20 wt % ofcarboxylic acids, based on the total weight of co-solvent (i.e excludingwater). There is no upper limit for the carboxylic acid concentration,but for practical purposes the co-solvent may comprise equal to or lessthan 90 wt %, more preferably equal to or less than 80 wt % ofcarboxylic acids, based on the total weight of co-solvent (i.e.excluding water). Preferably the co-solvent comprises at least aceticacid, levulinic acid and/or pentanoic acid. Especially acetic acid maybe useful for simultaneous use as a polar solvent as well as use as anacid catalyst.

In a preferred embodiment, the co-solvent comprises at least one or morepolar solvents chosen from the group consisting of acetic acid,levulinic acid and gamma-valerolactone or mixtures thereof. Morepreferably the co-solvent is essentially free of other compounds.

In one preferred embodiment, as indicated also above, the co-solventcomprises one or more polar solvent(s) that are at least partly obtainedand/or derived from the cellulosic, preferably lignocellulosic, materialused as a feedstock in the liquefaction process of the invention itself.Any polar solvent obtainable from the cellulosic material liquefiedaccording to the process of the invention may advantageously begenerated in-situ and/or recycled and/or used as a make-up solvent inthe liquefaction process, affording significant economic and processingadvantages.

In a preferred embodiment any recycle of the solvent mixture comprises aweight amount of solvent mixture of 2 to 100 times the weight of thecellulosic material, more preferably of 5 to 20 times the weight of thecellulosic material.

In another preferred embodiment the co-solvent comprises one or morepolar solvent(s) that are at least partly obtained and/or derived from asource other than the cellulosic material used as a feedstock in theliquefaction process of the invention itself, for example a petroleumsource. These one or more polar solvent(s) may for example be mixed withthe cellulosic material before starting the liquefaction process or maybe added to the reaction mixture during the liquefaction process.

In a preferred embodiment the co-solvent comprises at least one or morecarboxylic acids, such as for example acidic acid, levulinic acid and/orpentanoic acid, which carboxylic acid is preferably present beforebeginning the reaction, that is, which carboxylic acid is not in-situobtained and/or derived from the cellulosic material during thereaction.

The co-solvent comprising one or more polar solvents is preferablypresent in an amount of less than or equal to 90% by weight and mostpreferably less than or equal to 80% by weight, based on the totalweight of water and co-solvent. Further the co-solvent comprising one ormore polar solvents is preferably present in an amount of more than orequal to 15% by weight and most preferably more than or equal to 20% byweight, based on the total weight of water and co-solvent. Theco-solvent, comprising one or more polar solvents, is preferably presentin an amount of from 10% to 80% by weight, and more preferably 20% to70% by weight, most preferably from 20 to 60% by weight, based on thetotal weight of the water and co-solvent.

Preferably water is present in an amount of less than or equal to 85% byweight, more preferably less than or equal to 80% by weight, based onthe total weight of water and co-solvent. Further water is preferablypresent in an amount of more than or equal to 10% by weight, morepreferably 20% by weight, based on the total weight of water andco-solvent. Preferably, water is present in an amount of from 20% to 90%by weight, more preferably from 30% to 80% by weight, most preferablyfrom 40% to 80% by weight based on the total weight of the water andco-solvent.

Preferably the solvent mixture contains the co-solvent and water in aweight ratio of co-solvent to water of less than or equal to 9:1, morepreferably less than or equal to 8:2. Further the solvent mixturepreferably contains the co-solvent and water in a weight ratio ofco-solvent to water of more than or equal to 1:9 more preferably morethan or equal to 2:8.

The cellulosic material and the solvent mixture containing water andco-solvent, are preferably mixed in a solvent mixture-to-cellulosicmaterial ratio of 2:1 to 20:1 by weight, more preferably in a solventmixture-to-cellulosic material ratio of 3:1 to 15:1 by weight and mostpreferably in a solvent mixture-to-cellulosic material ratio of 4:1 to10:1 by weight.

The hydrogenation catalyst may be any hydrogenation catalyst that isresistant to the combination of the solvent mixture and the acidcatalyst.

For example the hydrogenation catalyst can comprise a heterogeneousand/or homogeneous catalyst. In a preferred embodiment the hydrogenationcatalyst is a homogeneous catalyst. In another preferred embodiment thehydrogenation catalyst is a heterogeneous catalyst.

The hydrogenation catalyst preferably comprises a hydrogenation metalknown to be suitable for hydrogenation reactions, such as for exampleiron, cobalt, nickel, copper ruthenium, rhodium, palladium, iridium,platinum and gold, or mixtures thereof.

If the hydrogenation catalyst is a heterogeneous catalyst, the catalystpreferably comprises a hydrogenation metal supported on a carrier.Suitable carriers include for example carbon, titanium dioxide,zirconium dioxide, silicon dioxide and mixtures thereof. Examples ofpreferred heterogeneous hydrogenation catalysts include ruthenium,platinum or palladium supported on a carbon carrier. Other preferredexamples of heterogeneous hydrogenation catalysts include rutheniumsupported on titanium dioxide (TiO2), platina supported on titaniumdioxide and ruthenium supported on zirconium dioxide (ZrO2). Theheterogeneous catalyst and/or carrier may have any suitable formincluding the form of a mesoporous powder, granules or extrudates or amegaporous structure such as a foam, honeycomb, mesh or cloth. Theheterogeneous catalyst may be present in a liquefaction reactorcomprised in a fixed bed or ebullated slurry. Preferably theheterogeneous catalyst is present in a liquefaction reactor as a fixedbed.

If the hydrogenation catalyst is a homogeneous hydrogenation catalyst,the catalyst preferably comprises an organic or inorganic salt of thehydrogenation metal, such as for example the acetate-, acetylacetonate-,nitrate-, sulphate- or chloride-salt of ruthenium, platinum orpalladium. Preferably the homogeneous catalyst is an organic orinorganic acid salt of the hydrogenation metal, wherein the acid is anacid which is already present in the process as acid catalyst orproduct.

The source of hydrogen may be any source of hydrogen known to besuitable for hydrogenation purposes. It may for example include hydrogengas, but also an hydrogen-donor such as for example formic acid.Preferably the source of hydrogen is a hydrogen gas. Such a hydrogen gascan be applied in the process of the invention at a partial hydrogenpressure that preferably lies in the range from 2 to 200 bar (absolute),more preferably in the range from 10 to 170 bar (absolute), and mostpreferably in the range from 30 to 150 bar (absolute). A hydrogen gascan be supplied to a liquefaction reactor co-currently, cross-currentlyor counter-currently to the cellulosic material. Preferably a hydrogengas is supplied counter-currently to the cellulosic material.

The liquefaction process according to the invention can be carried outat any total pressure known to be suitable for liquefaction processes.The process can be carried out under a total pressure that preferablylies in the range from 2 to 200 bar (absolute), more preferably in therange from 10 to 170 bar (absolute), and most preferably in the rangefrom 30 to 150 bar (absolute).

The liquefaction process according to the invention can be carried outat any temperature known to be suitable for liquefaction processes. Theprocess according to the invention is carried out at a temperature ofpreferably more than or equal to 50° C., more preferably more than orequal to 100° C. and still more preferably more than or equal to 150° C.and preferably less than or equal to 350° C., more preferably less thanor equal to 300° C. and even more preferably less than or equal to 250°C. More preferably, the process is carried out at a temperature of from150° C. to 250° C., most preferably from 180° C. to 220° C.

The liquefaction process according to the invention can be carried outbatch-wise, semi-batch wise and continuously. The reaction effluent ofthe process according to the invention may include so-called humins, theliquefied product and for example water, co-solvent, acid catalyst,and/or hydrogenation catalyst and/or gaseous products such as forexample hydrogen.

By humins is understood the solid insoluble material remaining afterliquefaction. It is sometimes also referred to as char.

The liquefied product may comprise monomeric and/or oligomeric compoundsand optionally excess water produced during the liquefaction process.From the liquefied product a product containing monomeric and oligomericcompounds can be obtained.

The reaction effluent is preferably forwarded to a separation section.In the separation section insoluble humins, monomeric and/or oligomericcompounds and/or water, co-solvent and/or acid catalyst can be separatedoff from the reaction effluent.

In one embodiment the humins may be separated from the reaction effluentin a manner known to be suitable for this purpose. Preferably suchhumins are separated off via filtration or settling. Any humins formedin the process according to the present invention can be converted todiesel, kerosene and gasoline fraction by conventional refiningtechnologies such as fluidized catalytic cracking or hydrocrackingand/or thermal cracking.

In another embodiment the liquefied products are separated from thereaction effluent in a manner known to be suitable for this purpose.Preferably liquefied products are separated off by liquid/liquidseparation techniques, such as phase separation, (solvent) extractionand/or membrane filtration or (vacuum) distillation.

If desired the monomeric products and oligomeric products may beconveniently separated from each other using one or more membranes. Forexample, monomeric compounds and/or optionally water can be separatedfrom any C9-C20 oligomeric compounds and C20+ oligomeric compounds by aceramic membrane (for example a TiO₂ membrane) or a polymeric membrane(for example a Koch MPF 34 (flatsheet) or a Koch MPS-34 (spiral wound)membrane). The C9-C20 oligomers and the C20+ oligomers can convenientlybe separated from each other with for example a polymer grafted ZrO₂membrane. The use of membranes for these separations can advantageouslyimprove the energy efficiency of the process.

In another embodiment excess water produced during the liquefactionprocess is removed by distillation, pervaporation and/or reversedosmosis.

In a preferred embodiment, at least part of any water, co-solvent, acidcatalyst and/or hydrogenation catalyst is advantageously recovered to berecycled for re-use in the liquefaction process.

In a further preferred embodiment, this recycle stream also contains atleast part of any monomeric compounds and/or oligomeric products.

Any excess of water, co-solvent, acid catalyst, hydrogenation catalystsand/or monomeric compounds is preferably purged via a purge stream.

If desirable, the purge stream can be separated into a monomer-streamcontaining monomeric compounds and a water-stream containing water.Subsequently at least part of the monomer-stream can be used as a fuelprecursor and the water stream can be send to a water treatment plant.In addition part of the monomer-stream and/or the water stream can berecycled to the liquefaction reactor.

In the process of the invention, preferably more than or equal to 50% byweight, more preferably more than or equal to 60% by weight and mostpreferably more than or equal to 70% by weight of the cellulosicmaterial may advantageously be liquefied into liquefied product,preferably in less than 3 hours.

From the liquefied product a product containing one or more monomericcompounds and/or one or more oligomeric compounds can be obtained. Forexample when the liquefied product contains monomeric compounds,oligomeric compounds and excess water produced in the liquefaction,monomeric and/or oligomeric compounds and excess water may be separatedvia distillation or another suitable separation technique as describedabove. When the liquefied product consists essentially of monomericand/or oligomeric compounds, no specific recovery steps are needed toobtain the product containing one or more monomeric compounds and/or oneor more oligomeric compounds.

The product containing one or more monomeric compounds and/or one ormore oligomeric compounds preferably comprises in the range from 20 wt %to 80 wt %, more preferably in the range of 25 wt % to 75 wt %, of oneor more monomeric compounds having a molecular weight (Mw) of less thanor equal to 250 Dalton (Da); and/or in the range from 20 wt % to 80 wt%, more preferably in the range of 25 wt % to 75 wt %, of one or moreoligomeric compounds having a molecular weight (Mw) of more than 250Dalton (Da). More preferably the liquefied product can comprise aproduct that consists essentially of in the range from 20 wt % to 80 wt%, more preferably in the range of 25 wt % to 75 wt %, of one or moremonomeric compounds having a molecular weight (Mw) of less than or equalto 250 Dalton (Da); and in the range from 20 wt % to 80 wt %, morepreferably in the range of 25 wt % to 75 wt %, of one or more oligomericcompounds having a molecular weight (Mw) of more than 250 Dalton (Da).

The weight ratio of the monomeric compound(s) to the oligomericcompound(s) preferably lies in the range from 4:1 to 1:4, morepreferably in the range from 3:1 to 1:3. The oligomeric compoundspreferably comprise less than or equal to 50 wt %, more preferably lessthan or equal to 40 wt % of tar, based on the total weight of oligomericcompounds. There is no lower limit for the weight percentage of tar butin practice the weight percentage of tar can be more than 1 wt % or 3 wt%, based on the total weight of the oligomeric compounds.

Further the oligomeric compounds preferably comprise more than or equalto 50 wt %, more preferably more than or equal to 40 wt % of theoligomeric compounds that are liquid at ambient temperature (20° C.) andpressure (1 bar absolute), based on the total weight of oligomericcompounds. There is no upper limit for the weight percentage ofoligomeric compounds that are liquid at ambient temperature (20° C.) andpressure (1 bar absolute) but in practice the weight percentage can beless than 97 wt % or 99 wt %, based on the total weight of theoligomeric compounds.

Hence in a preferred embodiment the product may comprise in the range of20 wt % to 80 wt % of one or more monomeric compounds; in the range of20 wt % to 80 wt % of one or more oligomeric compounds that are liquidat ambient temperature (20° C.) and pressure (1 bar absolute); and inthe range from 0 wt % to 25 wt % of tar.

As a result of the liquefaction process used, the oligomeric compounds,and optionally also the monomeric compounds, may have an advantageoushigh saturation level. The process of the invention thus advantageouslyallows one to minimize or abandon any subsequent hydrogenation processand/or to forward the produced oligomeric and/or monomeric compoundsdirectly to a subsequent hydrodeoxygenation and/or cracking unit.

The saturation level can be determined by calculating the percentage ofsp3 carbons atoms based on the total of sp3,sp2 and sp carbons atomsdetermined by means of ¹³C-NMR. The percentage of saturated carbon atomsin the fraction of oligomeric compounds (i.e. the percentage of sp3carbons, based on the total amount of carbons, as determined by ¹³C-NMRspectroscopy at a chemical shift below 100 ppm) is preferably more thanor equal to 35%, more preferably more than or equal to 50%, still morepreferably more than or equal to 60% and most preferably more than orequal to 70%, based on the total amount of carbon atoms present. Thepercentage of carbon atoms in the fraction of oligomeric compounds thatis saturated (i.e. the percentage of sp3 carbons, based on the totalamount of carbons, as determined by ¹³C-NMR spectroscopy at a chemicalshift below 100 ppm) may further be less than or equal to 99%, or lessthan or equal to 95%, or less than or equal to 90%, based on the totalamount of carbon atoms present.

When the monomeric compounds can be separated from the co-solvent, alsothe saturation level for the monomeric compounds can be determined bymeans of ¹³C-NMR. The percentage of saturated carbon atoms in thefraction of monomeric compounds (i.e. the percentage of sp3 carbons,based on the total amount of carbons, as determined by ¹³C-NMRspectroscopy at a chemical shift below 100 ppm) is preferably more thanor equal to 50%, more preferably more than or equal to 60%, still morepreferably more than or equal to 70% and most preferably more than orequal to 75%, based on the total amount of carbon atoms present. Thepercentage of saturated carbon atoms in a fraction of monomericcompounds (i.e. the percentage of sp3 carbons, based on the total amountof carbons, as determined by ¹³C-NMR spectroscopy at a chemical shiftbelow 100 ppm) may further be less than or equal to 99.9%, or less thanor equal to 99%, or less than or equal to 95%, based on the total amountof carbon atoms present.

By monomeric compounds is herein understood compounds that have amolecular weight (Mw) of less than or equal to 250 Dalton (Da).Preferably the monomeric compounds have a molecular weight (Mw) of atleast 50 Dalton (Da). The molecular weight can be determined by SizeExclusion Chromatography (SEC). The monomeric compounds, also sometimesreferred to as monomers, further preferably comprise compounds that havethe potential of chemically binding to other monomeric compounds of thesame species to form an oligomeric compound.

Preferably the product contains a mixture of two or more monomericcompounds. The monomeric compounds can include cyclic, branched and/orlinear compounds. The monomeric compounds preferably have from 1 to 20carbon atoms, more preferably from 4 to 17 carbon atoms. For example,the monomeric compounds preferably include C4 monomeric compounds, C5-C6monomeric compounds and/or lignin fragments. Preferably the monomericcompounds include tetrahydropyran (oxane) and/or substituted furanecompounds, substituted tetrahydrofurane compounds, substitutedtetrahydropyran compounds, substituted phenol compounds, substitutedguaiacol (orthomethoxyphenol) substituted syringol (di-orthomethoxyphenol) and/or various alcohols, ketones, carboxylic acids orcarboxylate esters. More preferably the monomeric compounds comprisesubstituted tetrahydrofurane, substituted tetrahydropyran, substitutedguaiacol and/or substituted syringol in an amount of more than or equalto 20 wt %, still more preferably more than or equal to 50 wt % and mostpreferably more than or equal to 70 wt %, based on the total weight ofmonomeric compounds.

An example of a C4 monomeric compound is 1-hydroxy-2-butanon. Examplesof C5-C6 monomeric compounds include C5-C6 unsaturated rings such as forexample 2-furancarboxaldehyde and 2-furanmethanol; and/or C5-C6saturated rings such as for example tetrahydro-2-furanmethanol,tetrahydro-2-methyl-furan, tetrahydro-2H-pyran (Oxane),tetrahydro-2H-pyran-2-ol, tetrahydro-2H-2-methyl-pyran,tetrahydro-2,5-dimethyl-furan and tetrahydro-2-hydroxy-5-methyl-furan;and/or C5-C6 linear ketones, esters acids and alcohols such as forexample 4-oxo-pentanoic acid, 2-pentanone, 2-hexanone, 1-hexanol,2,5-hexanedione and 1-pentanol. Examples of lignin fragments include2,6-dimethoxy-4-ethyl-1-phenol and 2-methoxy-4-ethyl-1-phenol.

The monomeric compounds and/or oligomeric compounds can advantageouslybe converted into gasoline components, such as ethyl valerate, methylfuran, ethyl furfuryl ether, methyl-tetrahydrofuran, esterified and/oretherified oligomers or other hydrocarbons by means of hydrogenation,esterification, etherification and/or dehdyration reactions.

In one embodiment of the invention, at least part of the monomericcompounds in the product is recovered and directly used as or convertedinto a fuel component, preferably a gasoline component.

By oligomeric compounds is herein understood compounds that have amolecular weight (Mw) of more than 250 Dalton (Da).

The molecular weight can be determined by Size Exclusion Chromatography(SEC). An oligomeric compound, also sometimes referred to as oligomer,further preferably consist of 2 to 15, more preferably 2 to 10, stillmore preferably 2 to 6 and most preferably 2 to 4 monomer units.

Preferably the product contains a mixture of two or more oligomericcompounds. The oligomeric compounds can include cyclic, branched and/orlinear compounds. The oligomeric compounds can include oligomericcompounds that are liquid at ambient temperature (20° C.) and pressure(1 bar absolute) and so-called tar. By tar is understood that part ofthe product that is solid at ambient temperature (20° C.) and pressure(1 bar absolute), but that melts when heated and/or dissolves in adifferent solvent. Preferably the oligomeric compounds that are liquidat ambient temperature (20° C.) and pressure (1 bar absolute) have amolecular weight (Mw) in the range of more than 250 Dalton (Da) up toand including 2000 Dalton (Da). The percentage of saturated carbon atomsin the oligomeric compound fraction that is liquid at ambienttemperature (20° C.) and pressure (1 bar absolute) is preferably morethan or equal to 50%, more preferably more than or equal to 60%, stillmore preferably more than or equal to 70%, based on the total amount ofcarbon atoms and less than or equal to 99.9%, or less than or equal to99%, or less than or equal to 95%, based on the total amount of carbonatoms.

The tar preferably has a molecular weight (Mw) from more than 2000Dalton (Da) up to and including 30000 Dalton (Da). In a furtherembodiment, preferably at least part of the liquefied product or atleast part of an obtained product comprising one or more monomericcompounds and/or one or more oligomeric compounds is converted into afuel component, preferably for a diesel or gasoline fuel. Morepreferably at least part of any oligomeric compounds is recovered andconverted to a fuel component, preferably for a diesel fuel. At leastpart of the liquefied product, the product comprising one or moremonomeric compounds and/or one or more oligomeric compounds, or theoligomeric compounds can be converted in any manner known to be suitablefor that purpose. The conversion may for example be carried out byfractionation, hydrodeoxygenation, catalytic cracking, thermal crackingand/or hydrocracking.

Preferably the conversion comprises at least hydrodeoxygenating and/orcracking to produce a fuel component or fuel component precursor.

More preferably at least part of the liquefied product or obtainedproduct containing monomeric and/or oligomeric compounds is at leastpartially hydrodeoxygenated, rendering it hydrocarbon soluble, prior tobeing blended with a refinery stream such as crude oil, (vacuum) gasoilor (heavy) cycle oil and being subjected to further hydrodeoxygenationor a thermal-, catalytic- or hydro-cracking processes. Thehydrodeoxygenation can be performed in any manner known to be suitablefor that purpose. For example the hydrodeoxygenation may be performedunder hydrodeoxygenation conditions in the presence of ahydrodeoxygenation catalyst. The hydrodeoxygenation catalyst may containa metal of any one of groups 8 to 11 of the Periodic Table of Elements.Following the initial hydrodeoxygenation step, the at least partiallydeoxygenated products can be recovered from the solvents, for example byliquid/liquid separation techniques, prior to possibly being subjectedto upgrading to a fuel component or fuel component precursor by means offurther hydrodeoxygenation or by thermal-, catalytic- or hydro-crackingprocesses.

The fuel component or fuel component precursor can be used in thepreparation of a biofuel such as a biodiesel, biokerosine orbiogasoline.

FIGS. 1 and 2 show illustrate two different processes according to theinvention.

In FIG. 1, a feed stream (1 a) comprising solid biomass, acid catalyst,homogeneous hydrogenation catalyst and solvent mixture (water andco-solvent); and a stream (2) comprising hydrogen gas are supplied to aliquefaction reactor (3). In liquefaction reactor (3) simultaneoushydrolysis and hydrogenation is carried out to produce an effluentstream (4) comprising liquefied product, humins, acid catalyst,homogeneous hydrogenation catalyst and solvent mixture (and optionallydissolved hydrogen gas). The effluent stream (4) is forwarded toseparation section (5). In separation section (5) the effluent stream(4) is separated into a stream (6) comprising insoluble humins, a stream(7) comprising liquefied product including oligomeric and, optionally,some monomeric compounds, and a stream (8) comprising solvent mixture(water and co-solvent), homogeneous hydrogenation catalyst and acidcatalyst and the remaining monomeric compounds (and optionally dissolvedhydrogen gas). Part of stream (8) is purged via a stream (9) and theother part is recycled via a stream (10) to liquefaction reactor (3).The purge stream (9) can optionally be treated to recover part of theco-solvent and/or acid for recycling to the liquefaction reactor (3).

A stream (11) comprising gaseous products including any unconvertedhydrogen leaves the liquefaction reactor (3) via the top.

In the process as illustrated by FIG. 1 the stream (2) comprisinghydrogen flows counter-currently to the stream (1 a) comprising solidbiomass, acid catalyst, homogeneous hydrogenation catalyst and solventmixture (water and co-solvent).

In FIG. 2, a feed stream (1 b) comprising solid biomass, acid catalyst,and solvent mixture (water and co-solvent); and a stream (2) comprisinghydrogen gas are supplied to a liquefaction reactor (3). The stream (2)comprising hydrogen flows co-currently to the stream (1 b) comprisingsolid biomass, acid catalyst, and solvent mixture (water andco-solvent). The liquefaction reactor (3) further contains heterogeneoushydrogenation catalyst in a fixed bed (12). The remaining numerals arethe same as in FIG. 1, except that streams (8), (9) and (10) do notcontain the hydrogenation catalyst.

In an alternative embodiment of the process of the invention (not shown)also part of the oligomeric compounds is recycled via streams (8) and(10) to the liquefaction reactor (3).

Throughout the description and claims of this specification, the words“comprise” and “contain” and variations of the words, for example“comprising” and “comprises”, mean “including but not limited to”, anddo not exclude other moieties, additives, components, integers or steps.

The invention will now be further illustrated by means of the followingnon-limiting examples and comparative examples.

Comparative Examples A, B and C and Examples 1-15

The experiments were performed according to the following conditions:

About 3.5 g of Birch wood (particle size <4 mm, semi-dried at 105° C.)was loaded into a 60 mL autoclave together with about 35 g of solventmixture which contained water, acetic acid co-solvent, acid catalyst andhydrogenation catalyst in a ratio as indicated in table 1. The weightratio of birch wood to reaction solution (that is the weight ratio ofbirch wood to the total sum of acid catalyst, hydrogenation catalyst,water and co-solvent) is also indicated in table 1. The weight ratio ofeach of the acid catalyst, hydrogenation catalyst, water and co-solventin the reaction solution (i.e. in the total sum of acid catalyst,hydrogenation catalyst water and co-solvent) is also indicated intable 1. For the hydrogenation catalyst only the weight % hydrogenationmetal is mentioned. The total of birch wood and reaction solution wasstirred (1400 rpm). The autoclave was sealed, pressurized to 50 bar ofH₂ (except for the comparative example) and heated to a temperature asindicated in table 1. Subsequently the H2 pressure was adjusted to thehydrogen pressure indicated in table 1. After a reaction time of 90 minthe autoclave was cooled to room temperature (20° C.) and opened andappropriate samples were taken.

The total product, including liquid, tar, insoluble humins and catalyst,was removed from the autoclave. The total product was subsequentlyfiltered over a P3 filter to produce a filtrate and a filter cake. Thefilter cake was washed with acetone and dried under vacuum (200 mbar) at50° C. overnight. The residual filter cake was weighted to determine theweight percentage of insoluble humins, based on the weight of birch woodfeedstock. Liquefaction was calculated as 100 wt %-wt % insolublehumins, based on the weight of birch wood feedstock.

The monomeric compounds were analysed by Gas Chromatography (GC) and acombination of Gas Chromatography and Mass Spectroscopy (GC/MS).

The oligomeric compounds were analyzed by means of Size ExclusionChromatography (SEC), using PL-gel polymer as immobile phase, THF asmobile phase and using Ultraviolet (UV, 254 nm wave length) andrefractive index (RI) detectors. Table 2 provides a summary of theproduct characteristics. The extent of liquefaction and the weightpercentages of insoluble humins, monomeric compounds and oligomericcompounds in table 1 were calculated based on the weight of birch woodfeedstock.

The molecular weight distribution of the oligomeric compounds wasdetermined between 150 and 30000 Dalton, using a series of polystyreneoligomer samples of known molecular weight as calibration.

The weight amount of oligomeric compounds was determined by RI using aseries of samples loaded with known weight amounts of lignin ascalibration.

Table 1 further includes a saturation index as a qualitative indicationof the extent of saturation of the oligomeric compounds. The saturationindex of the oligomeric compounds was determined, using a sample of a 1wt % solution of lignin (Organosols lignin no 37, 101-7 LN 12620MGobtained from Aldrich) in THF as calibration. The sample of lignin wasanalyzed with SEC as described above and the ratio of the amount oflignin detected by RI to the amount of lignin detected by UV was set tobe 1.0. Subsequently samples of solutions of the oligomeric compounds inTHF were analyzed with SEC and the ratio of the weight amount ofoligomeric compounds detected by RI to the weight amount of oligomericcompounds detected by UV was calculated for each sample. The saturationindex for each sample of oligomeric compounds can subsequently bedetermined against the lignin calibration as indicated in formula (I)

$\begin{matrix}{{{Saturation}\mspace{14mu} {index}} = \frac{\left\{ {\lbrack{Oligomer}\rbrack_{RI}/\lbrack{Oligomer}\rbrack_{UV}} \right\}}{\left\{ {\lbrack{lignin}\rbrack_{RI}/\lbrack{lignin}\rbrack_{UV}} \right\}}} & (I)\end{matrix}$

wherein[Oligomer]_(RI)=the weight concentration of oligomeric compounds asdetermined by the refractive index detectors;[Oligomer]_(UV)=the weight concentration of oligomeric compounds asdetermined by using Ultraviolet (254 nm wave length);[lignin]_(RI)=the weight concentration of oligomeric compounds asdetermined by the refractive index detectors; and[lignin]_(UV)=the weight concentration of oligomeric compounds asdetermined by using Ultraviolet (254 nm wave length).A higher saturation index indicates a higher degree of saturation. Asaturation index above 1 indicates a higher degree of saturation than inlignin.

As can be seen by comparing respectively comparative examples A, B and Cwith respectively examples 1-3, examples 4-7 and examples 8-10 and12-15, the process of the invention results in improved liquefaction anda higher level of saturation for the oligomeric compounds.

Abbreviations Used in Table 1 Include

BW birch woodAA acetic acid

W Water

TABLE 1 Process conditions for comparative examples A, B and C andexamples 1-15 BW (BW:W + AA Water Co-solv. Acid Acid cat. Hydr. Hydr.Cat. P(H2) Temp Time Exp wt ratio) (wt %) AA(wt %) cat. (wt %) cat (wt%) bar (° C.) (min) Comp A 1:10 68 29 H₂SO₄ 3 — 0.00  0^(a) 200 90 11:10 68 29 H₂SO₄ 3 Pd/C 0.37 80 200 90 2 1:10 68 29 H₂SO₄ 3 Pd(Ac)2 0.3180 200 90 3 1:10 68 29 H₂SO₄ 3 RuAcC1 0.29 80 200 90 Comp B 1:10 70 30 —0.0 Pd(Ac)2 0.33 80 200 90 4 1:10 69 30 H3PO4 1.4 Pd(Ac)2 0.33 80 200 905 1:10 67 29 H3PO4 3.3 Pd/C 0.33 80 200 90 6 1:10 70 30 H2SO4 0.3Pd(Ac)2 0.30 80 200 90 7 1:10 68 29 H2SO4 3.3 Pd(Ac)2 0.31 80 200 90Comp C 1:10 100 0 H2SO4 3.2 Pd(Ac)2 0.24 80 200 90 8 1:10 68 29 H2SO43.3 Pd(Ac)2 0.31 80 200 90 9 1:10 70 30 H2SO4 0.3 Pd(Ac)2 0.30 80 200 9010  1:10 40 60 H2SO4 0.4 Pd(Ac)2 0.32 80 200 90 11  1:10 70 29 H2SO4 0.3Pd(Ac)2 0.33 80 180 90 12  1:10 70 30 H2SO4 0.3 Pd(Ac)2 0.30 80 200 9013  1:10 68 29 H2SO4 3.3 Pd(Ac)2 0.31 80 200 90 14  1:5.5 68 29 H2SO43.3 Pd(Ac)2 0.32 80 200 90 15  1:4 68 29 H2SO4 3.2 Pd(Ac)2 0.31 80 20090

TABLE 2 Product characteristics for comparative examples A, B and C andexamples 1-15 Liquefaction Insol. Humins Oligomeric comp.* Monomericcomp. Saturation index for Exp (wt % on BW) (wt % on BW) (wt % on BW)(wt % on BW) oligomeric comp. Comp A 63 37 17 19 1, 4 1 95 5 13 25 2, 22 88 12 16 14 1, 6 3 90 10 15 18 2, 1 Comp B 68 32 20 23 2, 6 4 81 19 2224 1, 9 5 90 10 12 32 2, 4 6 93 7 21 24 2 7 88 12 16 14 1, 6 Comp C 7822 11 19 1, 8 8 88 12 16 14 1, 6 9 93 7 21 24 2 10  92 8 30 25 1, 2 11 74 26 23 20 2, 6 12  93 7 21 24 2 13  88 12 16 14 1, 6 14  81 19 12 151, 4 15  86 14 12 14 1, 7 Only oligomeric compounds being liquid at 20°C. and 1 bar absolute were included.

Example 16

About 3.3 g of Birch wood (particle size <4 mm, semi-dried at 105° C.)was loaded into a 60 mL autoclave together with about 0.1 gram ofPalladium as Pd/C catalyst, 21 grams of water, 9 grams of acetic acid,and 0.1 gram of sulphuric acid (H2SO4).

The autoclave was sealed, pressurized to 50 bar of H₂ (except for thecomparative example) and heated to a temperature of 200° C. Subsequentlythe H2 pressure was adjusted to 80 bar. After a reaction time of 90 minthe autoclave was cooled to room temperature (20° C.) and opened andappropriate samples were taken.

The total product, including liquid, tar, insoluble humins and catalyst,was removed from the autoclave. The total product was subsequentlyfiltered over a P3 filter to produce a filtrate and a filter cake. Thefilter cake was washed with acetone and dried under vacuum (200 mbar) at50° C. overnight. The dissolved oil (a mixture of monomeric andoligomeric compounds) was analyzed by means of GC, GC/MS, SEC and¹³C-NMR. A fraction of the dissolved oil was dried under vacuum and theresidual oil (mainly oligomeric compounds liquid at 20° C. and 1 barabsolute) was analyzed again by all the methods mentioned above.

In table 3 a product distribution is provided.

Furthermore table 4 lists the extent of unsaturation of the monomericand oligomeric fraction as determined by ¹³C-NMR.

TABLE 3 product distribution for example 16 Product wt % on BW monomeric33 oligomeric 14 Tar n.d. Humins 10 Total  67** **part from the BirchWood may have been converted to water and gaseous products not listed intable 3, as a result the total is less than 100 wt %

TABLE 4 ¹³C-NMR analysis of liquefied product for example 16 Total ofMonomeric and Oligomeric oligomeric compounds Chemical compounds* only*Function shift (ppm) (% carbon) (% carbon) >C═O >200 7 2 >C(O)O— 160-1804 7 >C═C< 100-160 13 18 Total sp2 >100 24 27 >C—O—  60-100 18 19 C—C <60 58 54 Total sp3 <100 76 73 Only oligomeric compounds being liquidat 20° C. and 1 bar absolute were included.

Examples 17 and 18

The experiment as described in example 16 was scaled up by a factor of−5 using the process characteristics as listed in table 5.

The listed amounts of Birch wood (BW, particle size <4 mm, semi-dried at105° C.), Palladium (Pd) as Pd-acetate catalyst (only grams metallisted), Water (W), Acetic Acid co-solvent (AA), and sulfuric acid(H2SO4) were loaded into a 250 mL autoclave.

The autoclave was sealed, pressurized to 50 bar of H₂ (except for thecomparative example) and heated to a temperature of 200° C. Subsequentlythe H2 pressure was adjusted to 80 bar. After a reaction time of 90 minthe autoclave was cooled to room temperature (20° C.) and opened andappropriate samples were taken.

The total product, including liquid, tar, insoluble humins and catalyst,was removed from the autoclave. The total product was subsequentlyfiltered over a P3 filter to produce a filtrate and a filter cake. Thefilter cake was washed with acetone and dried under vacuum (200 mbar) at50° C. overnight. The acetone solution was dried and the residue (tar)was weighted. The dissolved oil (a mixture of monomeric and oligomericcompounds) was analyzed by means of GC, GC/MS, SEC and ¹³C-NMR. Afraction of the dissolved oil was dried under vacuum and the residualoil (oligomeric compounds liquid at 20° C. and 1 bar absolute) wasanalyzed again by all the methods mentioned above. The tar (oligomericcompounds that are solid at 20° C. and 1 bar absolute but become liquidupon melting or dissolution) are analyzed by SEC and ¹³C-NMR.

The obtained product distribution is also reflected in table 5.Furthermore table 6 lists the extent of saturation of the tar fractionas determined by ¹³C-NMR in example 18.

TABLE 5 Process characteristics and Product distribution. Ex. 17 18Process characteristics (intake in grams) BW (dry) 16 23 Pd as Pd(Ac)21.0 1.4 W 105 71 AA 45 30 H2SO4 0.5 0.7 Product distribution (wt % onBW) monomeric 36 30 oligomeric 25 21 Tar 10 13 Humins 12 9 total 83 73

TABLE 6 ¹³C-NMR analysis of tar in example 18 Chemical Tar Functionshift (% carbon) >C═O >200 4 >C(O)O— 160-180 5 >C═C< 100-160 28 Totalsp2 >100 37 >C—O—  60-100 11 C—C  <60 52 Total sp3 <100 63

Example 19

About 3.5 g of Birch wood (particle size <4 mm, semi-dried at 105° C.)was loaded into a 60 mL autoclave (Hastelloy® C22® alloy) together withwater (21 g), acetic acid (9 g), sulphuric acid (0.1 g) and Pd/C (2 g,containing 0.1 g Pd).

The autoclave was closed and pressurised with H₂ to 50 bar. Subsequentlythe autoclave content was heated in 10-15 min to the reactiontemperature (200° C.), after which the hydrogen (H₂) pressure wasadjusted to 80 bar. The hydroliquefaction was continued for 90 minutes.As a result of H₂ consumption a small pressure drop of 10-20 bar wasobserved. The hydroliquefaction was stopped by rapidly reducing thetemperature to <10° C., subsequently the hydrogen was vented.

After opening the autoclave, the total product, including liquid, tar,insoluble humins and catalyst, was removed from the autoclave. The totalproduct was subsequently filtered over a P3 glassfilter to produce afiltrate and a filter cake.

The filter cake, containing insoluble humins and catalyst, was washedwith 50 ml acetone and dried overnight at 50° C. under vacuum (100-150mbar) The dried filter cake was weighted to determine the weightpercentage of insoluble humins, based on the weight of birch woodfeedstock. After corrections for the catalyst, the humins yield was0.2-0.3 gram; <10 w % based on the weight of birch wood feedstock).

The filtrate contained monomeric compounds, oligomeric compounds andwater. The monomeric compounds and oligomeric compounds were extractedfrom the water by means of liquid-liquid extraction usingmethyltetrahydrofuran.

The monomeric compounds were analyzed by GC/MS. The molecular structuresof some of the monomeric compounds found are given in FIG. 3. Where noelement is indicated the element is hydrogen. The monomeric compoundsfound included tetrahydropyran, methyl-tetrahydropyran andhydroxymethyltetrahydropyran. The tetrahydropyran,methyl-tetrahydropyran and hydroxymethyltetrahydropyran canadvantageously be blended with other components into a biofuel. Withoutwishing to be bound by any kind of theory it is believed thattetrahydropyrans have a higher volumetric energy density (i.e. energyper liter) than methyltetrahydrofurans (i.e. isomers with the sameatomic composition).

1. A process for liquefying a cellulosic material to produce a liquefiedproduct, which process comprises contacting the cellulosic materialsimultaneously with (a) an acid catalyst; (b) a solvent mixturecontaining water and a co-solvent, which co-solvent comprises one ormore polar solvents and which co-solvent is present in an amount of morethan or equal to 10% by weight and less than or equal to 95% by weight,based on the total weight of water and co-solvent; (c) a hydrogenationcatalyst; and (d) a source of hydrogen.
 2. The process of claim 1wherein the co-solvent is a solvent having a polarity of log P less than+1.
 3. The process of claim 1 wherein the co-solvent comprises at leastpart of the liquefied product, which part of the liquefied productcomprises one or more polar solvents.
 4. The process of claim 1 whereinthe acid catalyst is a mineral or organic acid having a pKa in waterbelow 3.75.
 5. The process of claim 1 wherein the hydrogenation catalystis a homogeneous catalyst or a heterogeneous catalyst.
 6. The process ofclaim 1 wherein the source of hydrogen is a hydrogen gas that iscontacted with the cellulosic material in a countercurrent manner. 7.The process of claim 6 wherein the co-solvent comprises at least part ofthe liquefied product, which part of the liquefied product comprises oneor more polar solvents.
 8. A product comprising: (a) from 20 to 80 wt %of a monomeric fraction containing one or more monomeric compoundshaving a molecular weight (Mw) of less than or equal to 250 Dalton (Da);(b) from 20 to 80 wt % of an oligomeric fraction containing one or moreoligomeric compounds having a molecular weight (Mw) of more than 250Dalton (Da), wherein the percentage of saturated carbon atoms in theoligomeric fraction is more than or equal to 35%, based on the totalamount of carbon atoms present.
 9. The product of claim 8 wherein theone or more oligomeric compounds are liquid at ambient temperature (20°C.) and pressure (1 bar absolute).
 10. The product of claim 9 furthercomprising from 0 wt % to 25 wt % of tar.
 11. The product of claim 8wherein the weight ratio of the monomeric compound(s) to the oligomericcompound(s) lies in the range from 4:1 to 1:4.
 12. The product of claim8 wherein the product comprises tetrahydropyranic monomers and/oroligomers.
 13. A process for producing a biofuel component from acellulosic material, which process comprises (a) contacting thecellulosic material simultaneously with an acid catalyst, a solventmixture containing water and a co-solvent comprising one or more polarsolvents, a hydrogenation catalyst and a source of hydrogen to produce aliquefied product; (b) obtaining one or more monomeric compounds and/orone or more oligomeric compounds from the liquefied product obtained instep a) to produce a second product comprising one or more monomericcompounds and/or one or more oligomeric compounds; (c)hydrodeoxygenating and/or cracking at least a part of the second productobtained in step b) to produce a fuel component and/or fuel componentprecursor; (d) blending and/or processing the fuel component and/or thefuel component precursor to a biofuel.
 14. The process of claim 13wherein the second product obtained in step b) comprises one or moretetrahydropyranic monomers and/or oligomers.
 15. The process of claim 13wherein the biofuel is a biodiesel, a biokerosine or a biogasoline. 16.A biofuel obtainable by a process of claim
 13. 17. A biofuel comprisingone or more tetrahydropyranic monomers and/or oligomers.